This invention relates to radio receiver, and more particularly to a radio receiver including a muting circuit for suspending temporarily a voice output therefrom.
In order to select a broadcasting station having the optimum reception level from a plurality of broadcasting stations respectively transmitting a common broadcast program at different frequencies, the listener mutes or suspends temporarily the reception of one of such broadcasting stations during the reception thereof and senses a reception level of a different one thereof. At that time, a muting circuit is used to suspend temporarily the reception of the one broadcasting station (which may be called hereinafter "the present station").
In radio receivers including the muting circuit, it has been a common practice to immediately suspend the voice output therefrom in response to instructions for the suspension of the voice output, independently of the level of the voice output. This might result in the generation of clicks at the moment the voice output is suspended and particularly when the voice output is at its highest audio level. That is, the voice signal falls suddenly from it high to its null level, resulting in the occurrence of pulse noise. Accordingly, there has been proposed a method of preventing the generation of clicks by incorporating a time constant circuit into the muting circuit to thereby reduce a sudden change in level of the voice output upon the suspension thereof. However, that method has been unable to completely prevent the generation of clicks.
Accordingly, it is an object of the present invention to provide a new and improved radio receiver which is substantially free from any intermission of sound preceived by the listener upon the suspension of a broadcasting station now received by the receiver in order to sense a reception level of a different broadcasting station during the reception of the present station.